Warm up! On a piece of notebook paper, define the following: Chapters 19 & 20: Stress Topography Isostasy Take out your 18 study guide

Mountain Building

There are three main ways to make a mountain: 1) compression force collision boundary Examples: Himalayas, Appalachians

There are three main ways to make a mountain: 2) tension stress Fault-block mountains Examples: Sierra Nevada (CA), Grand Tetons (WY)

There are three main ways to make a mountain: Rift valley 3) volcanoes divergent boundary subduction boundary hot spots New Island Forms Examples: Iceland, East African Rift trench volcanic mountains Examples: Cascades, Andes Example: Hawaii

Plate Tectonics Review: Look for Mountains Forming in all 3 ways… Wilson Cycle - http://youtu.be/I_q3sAcuzIY

Most mountains are along continental margins continental margin – boundary between continental and ocean crust

active margin – along a plate boundary (YES – mtn. building) passive margin – not along a plate boundary (NO – mtn. building) Passive East Coast US Active West Coast US

What forces and faults are involved in mountain building? Shear Stress Tension Compression Squeezing Pulling Apart Sliding Past

3 types of stress: 1) compression – push together (like a convergent boundary) Compression Squeezing

3 types of stress: 2) tension – pull apart (like a divergent boundary) Pulling Apart

3 types of stress: 3) shear – pushed in two, opposite directions (like a transform boundary) Shear Stress Sliding Past

What happens to rocks that are stressed? They can bend into folds They can break along faults

4 types of faults: 1) normal fault – caused by tension hanging wall moves down

4 types of faults: 2) reverse fault – caused by compression hanging wall moves up

4 types of faults: 3) thrust fault – caused by very strong compression plane of the fault is not very steep

4 types of faults: 4) strike-slip fault caused by shear stress

Strike Slip Fault layers of rock slide by each other

Review: Identify Each type of fault 1. Normal 2. Reverse 4. 3. Thrust Strike-Slip

Folds in rock layers: anticline – top of a fold: looks like an “A”

Folds in rock layers: syncline – bottom of a fold: looks like it “sinks” Sideling Hill, MD

Folds in rock layers: limb – slope of a side of a mountain

Compression

Identify the 2 folds. syncline anticline

Local Geology Which province has the most folds?

Put it all together: On your own Stress Description Fault Plate Boundary Arrows showing motion of plates   1. Reverse 2. Divergent Shear Push together convergent Thrust compression Pull apart tension normal Slide past horizontally Strike-slip transform

Homework: Finish back of notes page on mountain building (review) Next: The Rock Cycle